1. Field of the Invention
This invention relates generally to a splice element and more particularly to a consumable block for use in alignment and splicing both single and multi-mode single optical cable fibers.
2. Description of the Related Art
Fusion splicing devices have been well known for some time and many of these devices are commercially available. One such device is described in U.S. Pat. No. 5,002,351 to Szanto et al, issued Mar. 26, 1991 entitled Splicer for Optical Fibers. This and other similar devices are equipped with costly, permanent, tungsten electrodes capable of withstanding many repeated uses.
Another such device is described in U.S. Pat. No. 5,146,527 to Mallinson issued Sep. 8, 1992. Mallinson's fusion splicer is designed to receive a consumable ferrule, having a bore through a central longitudinal axis, for accommodating two fiber ends for fusion within. A slot is formed in the ferrule into which permanent electrodes are temporarily inserted for fusing optical fibers positioned within the bore.
U.S. Pat. No. 4,598,974 to Munn et al, issued Jul. 8, 1986 describes an optical fiber connector having integral electrodes. Although Munn's device relates specifically to a connector having a pre-inserted optical fiber stub, it is possible to adapt this design to a fusion sleeve for fusing two unconnected optical fibers. However, it is believed that a limitation of Munn's connector is the cost related to assembling such sleeves that must be kept free of dust, debris and grease. In addition to these restrictions, it is difficult to mass-produce such sleeves because each electrode must be individually inserted into its respective opening in the sleeve, adding to the cost of assembly.
U.S. Pat. No. 5,222,171 to Straus issued Jun. 22, 1993 describes a sleeve similar to Munn's having integral electrodes and axial alignment means. In one embodiment shown in FIG. 10 of the Straus patent two pieces of metal are attached by an adhesive and act as electrodes on either side of tubular member. Each piece of metal has a hole and a transverse hole is formed in the tubular member. Application of electric current produces an arc from the edges of the holes, which fuse fiber ends therebetween. Although the Straus sleeve may work as described, placement of the electrodes in this manner, so that they are essentially parallel to one another on either side of the member, is not a preferred design and is costly to manufacture.
U.S. Pat. No. 5,582,671 to Harman et al issued Dec. 10, 1996 discloses a method of manufacturing a fusion-splicing block for optical fiber splicing. The fusion splicing block is a one-piece consumable fusion block for both aligning the ends of the optical fibers to be spliced and the electrodes used for fusing said optical fibers. The method further discloses manufacturing a plurality of fusion blocks from a single slab of non-conduction material by overlying the non-conduction material with a length of conducting material, bonding the conduction material to the non-conduction material, and cutting the slab into smaller fusion blocks.
U.S. Pat. No. 5,740,301 to Harman et al, issued Apr. 14, 1998 discloses the fusion splicing block with electrodes disposed on planar surface being the product of the method of manufacture of U.S. Pat. No. 5,582,671 disclosed hereinabove.
U.S. Pat. No. 5,717,813 to Harman et al, issued Feb. 10, 1998 discloses an optical fiber splice element that includes a base member having a fusion element for aligning optical fibers for fusion within. A covering member is provided for covering and forming an enclosure with the base member in a closed position. The covering member can be a separate member or alternatively can be in the form of a hinged lid. In all of these teachings the alignment block is manufactured as a single unit. Further the alignment block and the electrodes are manufactured as a single integral unit.
Although the Harman et al inventions works as described, the production of a precise alignment groove in a single piece of non-conducting substrate is difficult and expensive to produce in commercial quantities. Furthermore, each use of the Harman et al inventions requires the replacement of both the electrodes and the alignment block because they are a single integral unit.
Thus, there remains a need for an optical fiber splicing device that is easy and inexpensive to manufacture while at the same time providing for the effective splicing of optical fibers.